An extensible markup language (XML) document based on a schema of elements defined by data types may have element instances with different structures. This may be due to differences among the data types extending from base data types. XML schema definition (XSD) schemas are sometimes graphically represented on tree structures. One problem involves graphically representing extended data types. To accurately create an extensible stylesheet language transformations (XSLT) map for an element, a user needs to know if data elements are extendable, the data type names and namespaces, and child elements or attributes that are valid under each specific extending data type. Another problem is the management of extending data types. Some XSD schemas define many extending data types for the same base data type, which can be cumbersome for a developer.